It was a really nice try. Heritage Action (the activist arm of the conservative Heritage Foundation) invited Sen. Elizabeth Warren to speak at an event dedicated to phasing out the Export-Import Bank.

The Ex-Im, as it’s known inside the Beltway, has become a favorite target of populist forces on the right. It gives taxpayer-backed loan guarantees to the foreign customers of giant US corporations that don’t need the help. It socializes the risk while privatizing the profits.

Basically, it’s free money for big businesses like GE, Caterpillar and particularly Boeing (hence the outfit’s nickname, “the Bank of Boeing”). Even Barack Obama, shortly before he became president, derided Ex-Im as “little more than a fund for corporate welfare.”

Ex-Im is up for reauthorization in September. Not surprisingly, both the people who get free money and the people who enjoy giving out money that doesn’t belong to them would like to continue doing so.

Since Warren is the dashboard saint of left-wing populism these days, denouncing big business and Wall Street at every turn, the puckish policy pixies at Heritage Action thought they could enlist her in their cause.

As first reported by Bloomberg News, Heritage wrote asking her to speak against Ex-Im “and the political favoritism it engenders.”

“We, like you, are frustrated with a political economy that benefits well-connected elites at the expense of all Americans,” Heritage Action head Michael Needham wrote. “Your presence will send a clear signal that you are going to fight the most pressing example of corporate welfare and cronyism pending before Congress right now.”

Warren didn’t take the bait. Her spokeswoman told Bloom­berg, “Sen. Warren believes that the Export-Import Bank helps create American jobs and spur economic growth, but recognizes that there is room for improvement in the bank’s operations.”

I think we’re seeing why there will never be a bipartisan left-right alliance against crony capitalism and corporate welfare.

The right’s “libertarian populism” wants to separate big business and big government. That means no more “too big to fail” and no more of government picking winners and losers.

The left’s anti-big-business populism is very different. It doesn’t want to cut the government’s incestuous relationship with big business; it simply wants to bring big business to heel.

Big business should do what Washington tells it to do. When it does, it will get treats. When it doesn’t, it will get the newspaper to the nose. But big business will never be let off its leash, if the left has its way.

“Warren doesn’t have a problem with big banks or corporations,” The Federalist’s David Harsanyi writes.

“She has a problem with banks and corporations that make profits in ways that she finds morally intolerable. She is an opponent of dynamism, not cronyism.”

This has always been the central idea behind progressive economics. Bureaucrats and other planners need ever more power to decide how economic resources are arranged and allocated. That doesn’t mean they’re socialists, it just means that corporations need to follow their lead.

Indeed, good “corporate citizenship” means acquiescing to the priorities of progressive state planners and whatever their latest idea of “public-private partnerships” might be. The one constant in such partnerships is that business is always the junior partner.

This was the vision behind Woodrow Wilson’s “war socialism,” FDR’s New Deal, LBJ’s Great Society, Bill Clinton’s “Third Way” and virtually all of President Obama’s economic policies.

What is ObamaCare but an attempt to turn the entire health-care industry into Washington’s well-fed lapdog?

What’s amazing is that people are still capable of shock when it turns out that a policy of treating businesses like dependent lapdogs yields businesses that try to have the government’s lap all to themselves.

Warren is famous for believing that businesses didn’t build their own success. According to her, businesses depend on government the way a lapdog depends on its master.

Asking her to oppose the Export-Import Bank is like asking her to punish a dog for rolling over.